Unknown gunmen in an ambush on a police vehicle in a Pakistani tribal area killed three and wounded two others, said police Thursday. The attack came late on Wednesday in Bannu district near North Waziristan tribal agency, a local senior police officer told KUNA on the condition of anonymity. He said the gunmen took away police vehicle, adding that they killed three policemen and critically wounded two others. The attack came a day after three militiamen were killed and three were wounded when their jeep hit a roadside bomb on Miramshah-Bannu road.